Both the front and back cover advertise four pieces by Wilm including a Capriccietto- the Aus italien set Op.161 (published 1898; no.2 is a Capriccietto). The next page then says Op.188-1: Capriccietto, which is the main evidence that that, and not Op.161-2, is what we're dealing with here. And that is how it is catalogued by Case Western, as Op.188/1, but - one suspects this could be Op.161-2. Hrm.